Cracking and Healing of Engineered Cemetitious Composites under Chloride Environment

Abstract

Engineered cementitious composite's (ECC) tensile ductility and microcracking behavior are essential for achieving structural durability (for example, corrosion resistance). This paper investigated ECC's durability in terms of maintaining its unique tensile characteristics under combined mechanical loading and aggressive chloride conditions. ECC specimens were preloaded to 0.5, 1.0, and 1.5% tensile strain levels; immersed in chloride solution for 30, 60, and 90 days; and reloaded until failure. This study revealed that the reloaded specimens retained multiple microcracking behavior and tensile strain capacity greater than 2.5%, while the average crack width increased from 50 µm to 100 µm. Self-healing in ECC under chloride exposure is evident in terms of recovery of initial material stiffness and tensile strain capacity. Subsequent studies at the microstructure scale explained the macroscopic composite behavior. These results indicated that under severe marine environmental conditions, ECC remains durable and provides reliable tensile ductility and crack-controlling capability to prevent the localized cracking failure often observed in concrete structures.